This invention relates to transport of signals of different protocols.
With the increase in communication traffic, networks are being demanded to be faster and larger in capacity. Large-capacity transport owing to data multiplexing has come to be used in backbone communication networks that connect line concentrators, bases, or providers' networks to each other. Examples of this large-capacity transport include Synchronous Digital Hierarchy/Synchronous Optical Network (SDH/SONET) in which low-rate signals are multiplexed into a signal of a predetermined rate to be transported as the signal, and Optical Transport Network (OTN) which accomplishes large-capacity transport by employing the concept of an optical path that is suitable for wavelength division multiplexing (WDM).
In this situation, for example, in JP 2003-143097 A, there is disclosed a technology in which the detection of synchronization among a plurality of frame rates in SDH or SONET is accomplished with a single circuit. In recent years, the diversification of signals (protocols) coupled to a network, which reflects their different uses, has also been observed. The link layer, for instance, has a mixture of various protocols such as Ethernet (trademark), Fibre Channel, and InfiniBand.
In JP 2012-142692 A, there is disclosed a technology with which pieces of equipment use a two-way communication line to hold communication to and from each other and to determine a transport path configuration for transporting digital signals between the pieces of equipment, such as the count of lanes to be used, the lane numbers of the lanes to be used, the transport direction, and the carrier clock frequency. A technology of transferring apparatus monitoring/control information with the use of a padding field is disclosed in JP 2005-269507 A.
The technology disclosed in JP 2003-143097 A detects, on the premise that transported signals are in the formats of SDH and SONET which are networks using synchronization protocols that heavily rely on accurate and stable clocks, multiple rates by detecting synchronization detection patterns unique to the respective formats. This technology therefore cannot detect signals of, for example, Ethernet which runs on asynchronous clocks.
Ethernet (trademark, the same applies hereinafter), which is capable of multiplexing signals that operate on asynchronous clocks, multiplexes signals by encoding processing, and is dependent on particular protocols because different protocols use different types of encoding, for example, 8B/10B encoding for 10 GbE (E is an abbreviation for Ethernet), and 64B/66B encoding for 100 GbE. In addition, in multi-rate transport Ethernet where, for example, transport by 10 gigabits per second (Gbps)×4 lanes is used for 40-Gb Ethernet and transport by 10 Gbps×10 lanes or 20 Gbps×4 lanes is used for 100 GbE, simply detecting the transport rates of the respective lanes does not help to discriminate 40 GbE and 100 GbE from each other.
The technology disclosed in JP 2012-142692 A uses Extended Display Identification Data (EDID) read out of equipment to determine whether the High Definition Multimedia Interface (HDMI) standard, which is used in AV systems, of the equipment is new or old, and therefore cannot be applied to communication apparatus and the like. The technology disclosed in JP 2005-269507 A monitors the packet length and, when a packet is smaller than a given packet size, determines that the packet has a padding field and inserts monitoring information. The technology of JP 2005-269507 A is therefore not applicable to processing in the physical layer where packet processing is not executed.
The technology disclosed in JP 2012-142692 A detects multiple rates with the use of an optical module code which is identification information indicating the type of an optical module. This technology is therefore not applicable to apparatus in which an optical module is not installed.